Dedicated electronic percussion instruments, e.g., electronic drums, having a drum pad are known. An electronic drum is a percussion instrument in which the sound is generated by an electronic waveform generator or sampler instead of by acoustic vibration. Typically, when an electronic drum pad is struck (i.e., triggered), a voltage change is caused in an embedded piezoelectric transducer (piezo) or force sensitive resistor (FSR). The resultant signals are translated into digital waveforms, which produce the desired percussion sound assigned to that particular trigger pad. Most newer drum modules have trigger inputs for 2 or more cymbals, a kick, 3-4 toms, a dual-zone snare (head and rim), and a hi-hat. The hi-hat has a foot controller which produces open and closed sounds with some models offering variations in-between.
Percussion instrument functionality can be implemented on devices having a touchscreen, but without a dedicated drum pad. Examples of such devices include tablet computers and smart phones. However, the touchscreen of such devices are typically “on/off” and not velocity sensitive like most drum pads in dedicated electronic percussion instruments. This may inhibit the range of expression of such devices to less than that of acoustic drums or dedicated electronic percussion instruments. Also, touchscreen electronic percussion instruments typically do not take advantage of some of the characteristics of dedicated electronic percussion instruments. Further, the limited user interface space typically available in touchscreen devices limits the number of controls that can be offered concurrently. A need exists to provide gesture interfaces for percussion instrument functionality implemented on devices having a touchscreen interface, but no drum pad, and a limited touch surface area.